Hitachi Dynamic Tiering: An In-Depth Look at Managing HDT and Best Practices, Part 2 of 2

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HITACHI DYNAMIC TIERING (HDT): AN IN-DEPTH LOOK AT MANAGING HDT AND BEST PRACTICESBRANDON LAMBERT, SR. MANAGERMICHAEL ROWLEY, PRINCIPAL CONSULTANT AMERICAS SOLUTIONS AND PRODUCTS

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Hitachi Dynamic Tiering simplifies storage administration by automatically optimizing data placement in 1, 2, or 3 tiers of storage that can be defined and used within a single virtual volume. Tiers of storage can be made up of internal or external (virtualized) storage, and use of HDT can lower capital costs. Simplified and unified management of HDT allows for lower operational costs and reduces the challenges of ensuring applications are placed on the appropriate classes of storage.

By attending this webcast, you will

• Hear about what makes Hitachi Dynamic Tiering a unique storage management tool that enables storage administrators to meet performance requirements at lower costs than traditional tiering methods.

• Understand various strategies to consider when monitoring application performance and relocating pages to appropriate tiers without manual intervention.

• Learn how to use Hitachi Command Suite (HCS) to manage, monitor and report on an HDT environment, and how HCS manages related storage environments.

HITACHI DYNAMIC TIERING (HDT): AN IN-DEPTH LOOK AT MANAGING HDT AND BEST PRACTICES, PART 2 OF 2

WEBTECH EDUCATIONAL SERIES

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The HDT lifecycle

HDT performance basics

HDT basic guidelines

Monitoring HDT with Hitachi Tuning Manager

AGENDA

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The HDT lifecycle

HDT performance basics

HDT basic guidelines

Monitoring HDT with Hitachi Tuning Manager

AGENDA

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HDT LIFECYCLE

Turn on HDT Heat

Maps

Design HDT Environment

Plan ImplementDaily Operations (Monitor/Report)

Build HDT Pools

Migrate Into Pools

Add Daily Monitoring

Tune Configuration(HW, Cycle,

Apps, Policies)

Historical Performance

Trend

Consider HW Limits

What to Monitor

and Cycle

Capacity Trend/Plan

Relocation Reporting (Gradual or Erratic)

Performance Trend/

Troubleshoot

Adjust Configuration

Basic Trend Report (Cap./Perf.)

Implement

Cont. Daily

Monitor (Alarm)

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The HDT lifecycle

HDT performance basics

HDT basic guidelines

Monitoring HDT with Hitachi Tuning Manager

AGENDA

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HDT PERFORMANCE MONITORING

Back-end I/O (read and write) counted per page during the monitor period

Monitor ignores “RAID I/O” (parity I/O)

Count of IOPH for the cycle (period mode)or a weighted average (continuous mode)

HDT orders pages by counts high to lowto create a distribution function‒ IOPH vs. terabytes

Monitor analysis is performed to determine the IOPH values that separate the tiers

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Page 1 Page 999

IOPH DP-VOLs

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5

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Capacity 1 Capacity nnn

Pool

SN2

Monitoring

Aggregate the Data

Analysis

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POOL TIER PROPERTIES

Can display just the performance graph for a tiering policy

What is being used now in the pool in terms of capacity and performance

The I/O distribution across all pages in the pool. Combined with the tier range, HDT decides where the pages should go

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CAUTION ABOUT PERFORMANCE UTILIZATION (P%)

P% is only an approximation of tier utilization It is based on assumptions of read/write ratios (50-50) P% does not factor in RAID I/O (parity I/O) It should not be used to calculate I/O counts It should not be used to determine relative utilization at lower P% values

- P% is not accurate enough for comparing small differences P% is only used to signal that a tier may be overutilized P% cannot absolutely report that a problem exists Ignore P% unless it is over 60% Prior to V04+a continuous modes, P% uses the weighted average IOPH

values. In V04+A continuous mode uses the monitoring result of the last cycle (period mode value) for calculating P% performance utilization

A better measure of actual tier utilization is to use parity group utilization

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TIER RANGE VALUES

Tier range values dynamically change according to workload

Tier range values are always calculated to keep upper tiers generally full

Pages compete for upper tiers. Pages can be pushed down if more aggressive workloads come on the scene

Pages that do not remain “hot enough” (competitive) will demote

Newly active data on dormant (or new) pages or migrated volumes will need protection

- Policy settings work well

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The HDT lifecycle

HDT performance basics

HDT basic guidelines

Monitoring HDT with Hitachi Tuning Manager

AGENDA

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CHOOSING A MONITOR STRATEGY: RECOMMENDED START POINT

Start with continuous mode

Start with automatic

Start with 8-hour

Investigate Hitachi Tiered Storage Manager for custom scheduling of monitor and relocation cycles

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CHOOSING A MONITOR STRATEGY

Use tiering policies to protect or restrict tier use

3-tier pool‒ Liberally use ALL

‒ Use level 4 if Tier 1 use should be restricted (not used) and when Tier 2 is well configured

‒ Note that incorrectly using level 5 will cause performance issues

‒ Levels 1 and 2 can cause overcommitment (and waste) of Tier 1

‒ Levels 2, 3, and 4 can overcommit Tier 2

2-tier pool‒ Liberally use ALL

‒ Liberally use level 4 (or 3 or 5) if Tier 1 use should be restricted (not used) and when Tier 2 is well configured

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RELOCATION RATES

Standard relocation throughput is about 3TB/day

Write pending and MP utilization rate influences the pace of page relocation‒ When WritePending is 55%, 20-second wait is inserted per page

‒ MP utilization rate influences pacing‒ 60% or more: 6 pages or less in 5 seconds‒ 50-60%: 8 pages or less in 5 seconds‒ 40-50%: 10 pages or less in 5 seconds‒ 30-40%: 12 pages or less in 5 seconds‒ 30% or less: Unlimited

When SOM904 is ON, only 1 page is relocated per second ‒ For example, when page migration takes 600 ms, the next page

migration starts after sleep for 400 ms (1,000 ms - 600 ms)

‒ If page migration takes 1 second or more, the next page migration starts without sleep procedure.

‒ HDT relocate pages in less than 40MB/sec

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HDT TUNING SUMMARY

HDT tunes tier ranges dynamically (neither Hitachi Tuning Manager ((HTnM)) or Hitachi Tiered Storage Manager ((HTSM)) is used)

If a tier P% approaches 60% utilization, we aim to move I/O down a tier

‒ 60% sustained I/O to accommodate peaks and prevent queuing

‒ Tier range is increased, reducing the tier’s utilized capacity. All of the tier capacity will not be used – but that is better than overloading the tier with too much IOPH

If all tiers are over (60%/60%/60%), the pool is over utilized − tier ranges are increased again to share the problem

You can’t “lose storage” but you might put more I/O into a pool than it can handle

You should be looking for these situations, evaluating the issues, and adding capacity

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HDT TUNING SUMMARY

Do not underestimate the importance of Tier-3 performance‒ HDT will relocate dormant pages to Tier 3. If these pages become

active, Tier 3 must perform well enough to cope with some host I/O and relocation I/O

Tiering policy can be used to help or hinder ‒ Helps

Use level 3 or 4 to stage data into Tier 2 before it is needed Use level 1 or 2 to stage important data before “Mondays”

‒ Hinders When using level 1-4 on dormant data Leaving level 1 or 2 set too long

T% and R% should not be changed unless needed to artificially reduce capacity

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TIER SIZE MATTERS

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POOL CONSUMPTION MATTERS

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The HDT lifecycle

HDT performance basics

HDT basic guidelines

Monitoring HDT with Hitachi Tuning Manager

AGENDA

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HDT AND HTNM

All HDT-level reporting in HTnM is in Performance Reporter‒ Some point-in-time metrics are fed into Mobility

All HDT reports are custom created

A set of custom reports are included with this presentation

WHAT'S AVAILABLE TODAY

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HDT AND HTNM

Nine tables in Performance Reporter for HDP/HDT are

‒ VVOL Tier Type Configuration (Individual DP-VOL capacity info by tier)

‒ VVOL Tier Type I/O Information (Individual DP-VOL performance metrics by tier)

‒ HDP Pool Configuration (Design and Capacity Info)

‒ Pool Summary (Total Pool Performance Info)

‒ Pool Tier Type Configuration (HDT Pool Design and Capacity)

‒ Pool Page Relocation (HDT Pool Relocation Info)

‒ Pool Tier Page Relocation (HDT Tier Relocation Info)

‒ Pool Tier Type IO Information (HDT Tier Performance Info)

‒ Pool Tier Type Operation Status (HDT Tier Performance Info)

WHAT'S AVAILABLE TODAY

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HDT CAPACITY MANAGEMENT AT THE POOL

Time Stamp for Collection (Collected Every 8 Hours by Default)

Type of Pool (HDP/HDT)Pool Physical CapacityTotal Provisioned CapacityFree Physical CapacityUsed Physical CapacityPhysical Used %

HDP/HDT POOL UTILIZATION – USEFUL FIELDS

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HDT CAPACITY MANAGEMENT AT THE POOL

Reports on both HDP and HDT pools

Capacity metrics are in gigabytes

Using historical information in HTnM, reports detailing growth of the pool can be used for capacity trend analysis

Alerts can be set for pools including usage percentage and status as warnings for out-of-space conditions beyond alerts set in HDvM and SN2

HDP/HDT POOL UTILIZATION – NOTES

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HDT CAPACITY MANAGEMENT AT THE POOL

HDT POOL UTILIZATION BY TIER– USEFUL FIELDS

Media composition by TierFree Tier Physical CapacityUsed Tier Physical CapacityTotal Tier Physical Capacity Physical Tier Capacity Used

as % of PoolPhysical Tier Capacity Used

as Percentage of Tier

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HDT CAPACITY MANAGEMENT AT THE POOL

Capacity metrics are in gigabytes

Trend of size and usage of storage tiers can be obtained by trending total capacity, used capacity, usage percentage in pool, or usage percentage in tier

Alerts can be set for lower tiers to flag high capacity usage percentage for review. Low tiers by default have lowest utilization percentage due to HDT standard of writing to higher tiers first

HDT POOL UTILIZATION BY TIER – NOTES

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HDT CAPACITY AT THE DP-VOL

HDT V-VOL UTILIZATION BY TIER – USEFUL FIELDS

LDEV NumberTier NumberSize of volume in tier (in MB)Percent of used V-VOL capacity on each tier.

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HDT CAPACITY AT THE DP-VOL

Large capacity proportion (85+%) in single tier may indicate HDT is not suitable for data type. Investigation of data workload/type and comparison to other workloads in pool is suggested

Large capacity proportion in high tier may indicate a need for verification of data type on volume‒ If high-performing but low-value data, use of tiering policy

may eliminate waste

A historical trend of capacity movement between tiers on V-VOL may indicate a poor candidate for HDT or a different HDT architecture required for volume

HDT V-VOL UTILIZATION BY TIER - NOTES

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HDT PERFORMANCE AT THE POOL

HDT POOL IOPS BY TIER – USEFUL FIELDS

Average IOPS Per Tier

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HDT PERFORMANCE AT THE POOL

Data is collected every 15 minutes

IOPS per tier can be used for historical data analysis and trending‒ View IOPS growth per tier over time

‒ Find tiers that are busy during specific cycles‒ Batch vs. transaction

‒ Backups

‒ Database maintenance

‒ Business vs. after hours

HDT POOL IOPS BY TIER – NOTES

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HDT PERFORMANCE AT THE POOL

HDT POOL PERFORMANCE BY TIER – USEFUL FIELDS

Average IOPS Per TierAverage IOPS Percentage Utilization Per Tier

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HDT PERFORMANCE AT THE POOL

Data is collected every monitoring period

Average IOPS utilization percentage per tier is number of IOPS processed per tier compared with total IOPS per tier possible as defined by storage array (same as performance utilization (P%) in SN2)

Allows trending of IOPS and tier utilization over time

Alerts can be set on utilization to monitor when tier gets to standard load-sharing thresholds (60%) or overutilization point

HDT POOL PERFORMANCE BY TIER – NOTES

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HDT PERFORMANCE AT THE POOL

Average IOPS utilization percentage provides general insight on whether HDT design is correct

‒ High IOPS utilization in Tier 1 or 2 indicates Tier 1 may need additional drives/parity groups to support additional performance needs

‒ High IOPS utilization in Tier 3 indicates Tier 1 and/or 2 may need additional drives/parity groups to support additional performance needs

‒ Low IOPS utilization in a single tier indicates tier may be too large and can be maintained/reduced in subsequent pool changes

‒ Balanced IOPS utilization under 60% indicates a well-designed HDT pool

‒ Balanced IOPS utilization over 60% indicates a pool running low on performance growth capability

HDT POOL PERFORMANCE BY TIER – NOTES

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HDT PERFORMANCE AT THE DP-VOL

HDT V-VOL PERFORMANCE BY TIER – USEFUL FIELDS

Average IOPS Per Tier Per V-VOL

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HDT PERFORMANCE AT THE DP-VOL

Metrics collected every 15 minutes

Provides insight into how IOPS count is broken out by tier of storage per V-VOL

Can be used to look at specific V-VOL or application use of tiers of storage over historical periods

High IOPS count in low tier of storage with high concentration of pages in same tier may indicate additional research to determine if volume or application is good candidate for HDT ‒ Assuming tiering policy is not in place for V-VOL

HDT V-VOL PERFORMANCE BY TIER – NOTES

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HDT RELOCATION MONITORING

HDT POOL RELOCATION STATUS – USEFUL FIELDS

Pages Moved During Relocation Cycle

Relocation Progress Percentage During Relocation Cycle

Relocation Start and Stop Time

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HDT RELOCATION MONITORING

Collected after each relocation period

Progress percentage can be used in alerting customer if relocation didn’t complete

Relocation start and end times define how long a relocation cycle takes

Relocation cycles that barely finish during relocation window may indicate collection/relocation configuration needs adjustment

Time between relocation start and end divided by number of pages moved indicates page movement speed (rule of thumb is ~35 MB/sec)

HDT POOL RELOCATION STATUS - NOTES

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HDT RELOCATION MONITORING

HDT POOL TIER RELOCATION INFORMATION – USEFUL FIELDS

Promoted and Demoted Pages by Tier

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HDT RELOCATION MONITORING

Collected after each relocation period

Promoted pages defines how many pages were promoted out of this tier

Demoted pages defines how many pages were demoted out of this tier

HDT POOL TIER RELOCATION INFORMATION − NOTES

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QUESTIONS AND DISCUSSION

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UPCOMING WEBTECHS

2013 WebTechs

‒ Upgrade Your Enterprise with Hitachi Data Systems, December 4, 9 a.m. PT, noon ET

‒ 2014 schedule to be published soon.

Check www.hds.com/webtech for Links to the recording, the presentation, and Q&A (available next

week) Schedule and registration for upcoming WebTech sessions Questions will be posted in the HDS Community:

http://community.hds.com/groups/webtech

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